[Membrane proteins of active and inactive variants of Actinomyces sp. 26-115, a producer of actinomycin C].

Some properties of the membrane proteins of Actinomyces sp. 26-115, i. e. its active variant and a variant not producing actinomycin C were studied comparatively. The membrane proteins of both variants of all ages tested represented a heterogenous fraction including about 30 protein components with a molecular mass of 17000 to 500000. There were differences in the protein component composition of the active and inactive variants. The membrane proteins of the active variant contained much more disulfide bonds than those of the inactive variant. It was shown in the model experiments on the protein binding of the phospholipid-lecithin membranes that the membrane proteins of the active variant bound higher amounts of lecithin during the whole developmental cycle than those of the inactive variant. It is suggested that the membrane proteins of the active variant had conformation differences as compared to those of the inactive variant.